Cellphones sort of being used as GPS units to map the use of city spaces has been explored here.
The electronic maps of cellphone usage were overlaid with geographic and city street maps to produce real time electronic landscapes of the city.
Opportunities for new approaches to city planning and transportation via new urban studies facilitated by technology arise.
The link takes you to the technology section of the New York Times. It talks about three tech developments: 1.) iPhone Application that allows you to quickly do a product search, 2.) Solar panel manufacturer than can do the initial planning of your panels via satellite and 3.) Another mobile phone application that enables you to send video directly to YouTube without first downloading to a computer.